As a term, the ‘structure of informality’ aims to elucidate how informality is produced, and why it persists. I argue that informality is engendered through the informal/formal dialectic, which constitutes a multiscalar process that creates global inequalities across time and space. We can better understand informality by studying colonial socio-spatial inequalities created through urbanization. Taking seriously the arguments put forward by Cobbinah and Olajide, I argue that the structure of informality must also be applied to understand contemporary neocolonial practices in relation to sustainable development. These practices include the use and misuse of informality in relation to three topics: (1) as a mode of generating and sustaining socio-spatial and economic inequalities; (2) the nascent and undertheorized relationship between informality and climate change; and (3) the importance of understanding and theorizing global informality at the heart of sustainable development to influence policy and practice. These topics have grown in salience because of the global push towards decarbonization, and despite informality being a dominant mode of economic, spatial, and political life in most of the world. Informality lies at the heart of sustainable development, thus making it essential to re-energize debates on its structures, forms, and driving forces.